Feeding system for cultured species

ABSTRACT

A feeding system for cultured species including: (a) providing (i) a sensor able to detect feed particles passing through a sample area, and (ii) a control unit, including computer data storage media in communication with the sensor; and (b) detecting and discriminating feed particles that pass through the sample area; wherein the control unit is able to process information obtained from the sensor and regulate subsequent feed output based on algorithm parameters, said algorithm parameters determine the instantaneous feed rate of the cultured species to adjust and match the preferred feed values meted to the cultured species at any given time.

This invention relates to a system for feeding cultured species, and inparticular in relation to cultured fish species. The system is able toautomatically regulate feed output for the cultured species.

Wild species of fish introduced to aquacultures, and indeed semi wilddomesticated species, exhibit broad feeding cycles that reflect the verynature of the diversification of such species. Such feeding cycles areeffected by exogenous and endogenous factors that impose variations tothe broad pattern. Because of these variations, it is difficult to matchfeed output to the preferential feeding patterns of the cultured fishand thereby effect the ability to maximise the growth of the culturedfish. Such variations also effect the feeding efficiency resulting infeed wastage

Various systems are available that, to a certain extent regulate thefeed provided to aquaculture systems Such systems may include detectiondevices which are able to shut off the supply of feed if an amount offeed is detected above a minimum value. Such systems generally aremerely a "on/off" system and do not take into account the variousexogenous and endogenous factors that may effect the feeding pattern.Accordingly, feed wastage still occurs, and indeed the fish may also notbe fed to satiation.

It should however be appreciated that the system may have broaderapplications for use other than in the feeding of fish species, forexample the feeding of cultured crustaceans or indeed non-aquaticspecies For convenience, it is appropriate to describe the invention inreference to aquaculture species in particular.

It is an object of the present invention to overcome or at leastalleviate one or more of the difficulties associated with such systems.

The present invention resides in a feeding system for cultured speciesincluding:

(a) providing

i) a sensor able to detect feed particles passing through a sample area,and

ii) a control unit, including computer data storage media incommunication with the sensor; and

(b) detecting and discriminating feed particles that pass through thesample area;

wherein the control unit is able to process information obtained fromthe sensor and determine subsequent feed output based on algorithmparameters, said algorithm parameters regulate the instantaneous feedrate of the cultured species to adjust and match the preferred feedvalues meted to the cultured species at any given time.

The invention is able to identify and adapt the macro and micro changesin feeding behaviour in order to increase the feeding efficiency of thecultured species. The system according to the invention is able toensure that fish are fed to satiation (or below if required) whilemaintaining an efficient food conversion ratio.

The sensor of the present invention is able to detect a sample, orindeed the absolute amount of feed which passes through a population ofspecies occupying a particular aquaculture system. The system mayinclude an enclosure such as a net, pen, tank, pond or other enclosuresuitable for aquaculture. The information obtained by the sensor may beused by the control unit to regulate subsequent feed output.

Generally, the control unit of the invention incorporates computer datastorage media, interface circuitry, EPROM memory, RAM memory, batterybacked real-time clock, control button, LCD display together withappropriate software. The system may also include a switched source ofpower for activating existing feed dispensers.

Accordingly, the present invention further resides in computer datastorage media embodying computer software which functions according tothe following steps:

i) process information received from a sensor able to detect feedparticles in a sample area;

ii) discriminate feed particles from other particles passing within thesample area;

iii) determine the instantaneous feed rate of a cultured species withina defined system; and

iv) determine subsequent feed output based on algorithm parameters tomatch the preferred feed values meted to the cultured species at anygiven time.

The control unit is able to store the feeding history of the culturedspecies and to calculate an optimum feed regime based upon the storedhistory, and/or other parameters inputed by a user. The feed history maybe mapped over a period of time by monitoring the feeding behaviour ofthe cultured species relative to the feed output and the amount of feeddetected by the sensor.

The feed output is preferably controlled by the control unit. Thecontrol unit preferably has a learning ability to allow it to call onprior knowledge or memory to calculate appropriate instantaneoussettings. This learning ability is preferably encoded by software. Theprior knowledge, or stored history, is based on past events, includingfeeding meal rates and feeding periods, and is stored and averaged overa period of time.

The sensor may be any suitable sensing device capable of sensing theamount of feed passing through a sample area. The sensor may be anysensor able to measure the change in flux of particles passing through asample area, including measurement by optical, ultrasonic or otherdoppler effect. The sample area may be a small sample area within theaquaculture system, or indeed may be the entire aquaculture system. Thesensor should be able to discriminate between feed particles and otherforeign material.

A preferred sensor includes:

(i) a body having an aperture orientated in use to allow objects to passtherethrough;

(ii) at least one light emitter for projecting a band of light acrossthe aperture; and

(iii) at least one light receiver for detecting the amount of lightpassed across the aperture;

wherein, in use, the profile of an object passing through the apertureis determined ratiometrically by measuring the instantaneous change inlight level caused by the occlusion of light by the object.

Such a sensor may include collimating mirrors in order to direct thelight from the light emitter to the light receiver. Real-time analysisof the profile of the object passing through the aperture allows fordiscrimination between the feed pellets and other objects passingthrough the aperture and is able to determine the rate of which the feedparticles pass through the aperture.

A preferred sensor is described in co-pending Australian application PN6815 and subsequently as International application No. PCT/AV96/00751,the entire disclosure of which is incorporated herein by reference.

The sensor is generally used for underwater use. Accordingly, it ispreferred to have a sensor where the light receiver(s), lightemitter(s), collimating mirrors and other associated circuitry is basedwith a body. The body generally involves a material transparent to thewavelength of light used by the sensor. The general design allowsdifferent sensors with a range of apertures to be manufactured utilisingcommon operating principles and manufacturing techniques. The bodygenerally incorporates a planar configuration consisting of two opposingplates allowing the components of the sensor to be enclosed therein. Thebody may be fabricated from flat sheets, such as acrylic, polycarbonateor similar material either by machining or molding. The plates haverecessed areas which enclose the collimating mirrors, the light emittersand receivers and accompanying electronic systems. The opposing sheetsare bonded at the time of assembly to provide a completely water tightenclosure. The bonding technique may utilise adhesives, ultrasonicwelding or any suitable method, including the use of fastening bolts.

The underwater sensor may be submerged to a depth which is dependent onthe type of cage structure, average water conditions, the speciesfeeding behaviour, the number of species in the cage, the age of thespecies and the type of feed used. For example, fish feeding depth willalso alter under certain environmental and temporal conditions.

The control unit will generally control the feed dispensed to thecultured species. The control unit is able to utilise informationreceived from the sensor, and other parameters including "learnt"feeding history of the species and other inputed parameters.

Preferably, in a typical feeding pattern, the minimum feed value isdispensed for a short period of time of from, for example, half a secondto 60 seconds. The sensor is then able to determine the amount of feedparticles passing through the sample area. Information is then relayedto the control unit relating to the number of feed particles in thesample area relative to a predetermined value. The computer data storagemedia of the control unit is able to adjust subsequent output accordingto the information it receives. A typical feed cycle may include thesteps of;

(i) increasing the feed output if the number of feed particles in thesample area are below a predetermined value;

(ii) maintaining the feed output if the number of feed particles in thesample area are within a pre-determined threshold;

(iii) decreasing the feed output if the number of feed particles areabove a pre-determined value or discontinue feeding if the number offeed values are above a predetermined minimum value.

Preferably, the feed will be dispensed at intervals from about 1 secondto about 10 minutes. Most preferably, feed is disposed every 1 to 2minutes, although this may vary depending upon both the maximum andminimum predetermined instantaneous feed rate, and the feed distributorhardware.

In establishing the system according to the present invention, thesystem may further include the steps of:

(a) Establishing the relevant information relating to the setting ofalgorithm parameters prior to dispensing the minimum feed value. Suchalgorithm parameters may relate to factors such as minimum and maximumfeed values, feed increments, species type and number, and otherenvironmental considerations, such as water temperature.

(b) Calibrating the sensor to determine spatial configuration relatingto the sample area. For example, some calibration will be requireddepending upon the depth at which the sensor is likely to be placed,water turbulency, currents and other such factors. Calibration may alsobe required in order to allow the sensor to discriminate between thefeed particles and other matter, for example fish faeces.

(c) Comparing and adjusting the calibration of the sensor to compensatefor uncalibrated objects. Such additional calibration may be conductedduring the feeding cycle to allow for matters and other objects thatwere not previously considered. This may be an ongoing requirement, butgenerally, due to the ability of the software to learn, furthercalibration is not required.

The sensor and control unit are able to utilise electronic andstatistical methods to define food particles such as pellets as opposedto other foreign material.

The system itself may be monitored remotely by a hard wiredcommunication link to the control unit, or by radio communications or bymeans of a portable data log off. The system can operate independentlyof a communication link if required.

The system may incorporate multiple sensors through a single controllerand a single sensor or variations thereof.

Various algorithms are used in order to determine the instantaneous feedoutput. This may be achieved by an adaptive feeding algorithm whichutilises the underwater sensor to discriminate pellets and then "decide"on an appropriate feeding level. The system uses predetermined programsetting values as a starting point and over time software functionevaluates and optimises these settings based on the full pattern dataaccumulated.

The following description provides examples of the parameters that areused to establish ranges within which the algorithm can function.

System parameters (sensor calibration and program settings) areinitially set by the user or from pre-defined internal tables ofsettings. After a period of time (for example 1 week, enough data iscollected by the system for the system to automatically evaluate thebest or most appropriate feeding rate and frequency and/or sensorcalibration values, and to test whether the user defined settings areappropriate. Changes are made and the user is informed if there is asignificant shift.

The system temporally "maps" and stores the average cumulative feedingpatterns (feed output per time). The number of food particles countedover time and user generated system setting values. All these parameterscan change as fish get larger, feed size changes or environmental andseasonal factors such as temperature, photo period etc alter. The systemautomatically compares user settings to historical data and thenoptimises settings to accord with the current situation.

The system accomplishes this by comparing historical averages relevantto the species, average for size, stock density, culture unit type,seasonal variations such as water temperature and latitude. Variousparameters may then be varied automatically, for example such parametersinclude:

The maximum feed delivery (food amount/bio-mass of culture species/time)

The minimum feed delivery (food amount/bio-mass of culture species/time)

The duration of the meal

The number of meals per day

The distribution of daily feed intake per meal

The period between meals (sleep period)

The quantity and frequency of delivery of feed within a meal

The ratio of the quantity of feed particles counted in relation to theamount of food presented.

The feed particles generated through user inputed parameters iscalibrated and data is compared to the actual present calibrated valuesrecorded. When calibrated pellet values (user calibrated) appeardifferent to actual pellets sensed, the system will self adjust andinform the user. The system will then utilise these modified calibrationvalues. The user can then re-calibrate the sensor and then verify thatthe newly calibrated values are not significantly different to thesystems modified calibration values if required. This self analysisallows for the detection of potential changes in the pelletcharacteristics such as pellet density or shape, factors that the usermay not distinguish easily. The user will generally only distinguishchanges in pellet size (for example a change from a 4 mm diameter pelletto a 6 mm diameter pellet and will in this case re-calibrate the sensormanually.

Various program parameters may be incorporated into the system andadjusted by algorithm if deviations occur. The algorithm stores therequired information. Definitions of user entered and defined settingsmay include:

Sink Rate:

The sink rate (cm/second) of the pellet used in combination with thesensor depth is used to establish or give the algorithm a guide as towhen pellets will pass through a sample area. This allows the algorithmto sequence feed delivered to match the time when this feed should passthe sample area.

Depth:

This is the depth from the water surface to the sensor

Gain:

This is an adjustment which allows the user to eliminate "background"interference if present and depends upon the type of sensor used withthe system. The algorithm can automatically range the gain setting todetermine the most appropriate value at the time.

The control unit bases all operations on daily feeding programs withsettings defined by the user and modified based on historical datacollected by the system. Each program divides the day into intervals orsteps. These intervals are specified by means of a start time and a stoptime.

Sleep:

The sleep period is the period that the system does not operate inbetween feeding periods or meals.

Minimum Pause:

The minimum pause time is the shortest time between feed output eventsduring a meal and is determined initially by a system of pre-determinedvalues based on the species and stocking density and culture typefactors.

Maximum Pause:

The maximum pause is the maximum delay between feeder output events andis determined by the same factors as the minimum pause.

Minimum Sleep:

The minimum sleep time is the smallest time that the feeder will remaininactive after a feeding bout or meal has completed.

Maximum Sleep:

The maximum sleep time is the longest period that all operations aresuspended after a feeding bout. Over the day, the sleep period will autorange between the minimum and the maximum sleep settings to hone in onthe preferred temporal feeding pattern of the fish.

Minimum Feed:

This is the minimum amount of feed delivered

Maximum Feed:

This is the maximum amount of feed delivered by the feed distributor.

The upper limit can be constrained by the size of the cage, feed inspatial distribution pattern and maximum number of pellets ingested perfish per minute. The appropriate instantaneous intake rate is determinedby auto ranging between the minimum and maximum feed values.

Sensitivity:

Sensitivity is the level of feed detected that determines the subsequentfeed output outcome.

Meal Maximum:

The meal maximum sets the upper limit to the amount of food delivered ina meal, that is without a sleep period intervening before the systemwill warn the user or turn off automatically. This is a safeguardagainst over feeding due to malfunction of hardware.

Water current threshold:

When the water current reaches a threshold velocity and direction of thesystem will be turned off until the current and direction go below thethreshold. This will allow for the sensor to account for feed which maybe lost due to water movement.

The computer data storage media is able to adapt certain parameters asmay be required. Such parameters may include:

The instantaneous feed output, which is the actual amount of feeddelivered after the algorithm has analysed all circumstances.

The instantaneous feeding process that utilises user defined settingsand historical data to regulate the instantaneous feed output. This isdetermined by an instantaneous feeding algorithm.

The pattern recognition response determined by an algorithm analyseshistoric system settings, feeding pattern data and other factors tomodify the instantaneous feeding process, and therefore theinstantaneous feed input.

Object discrimination response to allow for and discriminate fromuncalibrated objects using statistical methods.

The window, or period during which the sensor is functioning, when theprobability of detecting calibrated objects is greatest:

The system of the invention may include the following process steps:

(A) determine historical system settings;

(B) modify current system parameters if necessary;

(C) set the feed distributor output to a minimum feed value;

(D) Record "background" events, that is uncalibrated objects outside ofthe sensing window and define the number of model groupings usingstatistical techniques;

(E) dispense the selected amount of feed;

(F) commence sensing just prior to the sensing window. Compareuncalibrated objects in the pre-sensing window to calibrated objects;

(G) compare pre window uncalibrated objects to window sensed objects andcompensate if necessary;

(H) adjust if necessary;

(I) measure any feed pellets which pass through the sensor;

(J) wait for a short period, for example, 1-60 seconds;

(K) if less than a predetermined threshold number of pellets werecounted and the feeder output is less than a predetermined maximumvalue, increase output of feeder by one increment;

if greater than the threshold number of pellets are counted, reduceoutput of feeder by an increment of its previous value,

if the number of pellets counted equals threshold or is within a band,maintain feeder output;

(L) if the feeder output determined is less than a predetermined minimumthen wait for a predetermined sleep time, for example 30 minutes to 1hour, and compare feed rate per time of day to historical information tooptimise sleep value. If pattern recognition response criteria has beenmet, then sleep for a predetermined period, then return to step (A).

All this information, both user inputed, and those adapted by the systemthrough use, allow for a feeding system that automatically adjusts tothe desired feeding regime of the cultured species. The feed outcome isbased upon prior inputed values, prior feeding pattern profiles andprior and present algorithm settings.

The system of the invention provides for an improvement in the feedconversion efficiency in feeding cultured fish species in particular.Determining tests in salmonids have shown a 5-20% improvement in feedconversion efficiency with a 10≧20% faster growth rate of the fish, anda more uniform fish size. There is also a more consistent fleshcharacteristic (pigment, fat content and texture), a reduction in feedwastage, and a shortening of production cycle by up to 1 to 5 months.There is also a general improvement in stock health due to satiationfeeding in each meal.

The system may also allow for some control of production/harvest byadopting a particular strategy, for example satiation feeding,restricted feeding or cyclical feeding.

It will be convenient to describe the invention by reference to theaccompanying drawings which illustrate some preferred embodiments of theinvention. Other embodiments of the invention are possible andconsequently the particularity of the accompanying drawings is not to beunderstood as surpassing the generality of the preceding description ofthe invention.

FIGS. 1 and 2 depict a schematic diagram of the embodiments of thecultured species feed system according to the invention.

FIGS. 3 and 4 relate to graphical representation of a typical feedingpattern for a fish species.

FIG. 5 represents an embodiment of a sensor arrangement shown in FIGS. 1and 2.

FIG. 6 represents a flow diagram of a typical feeding regime.

FIG. 1 schematically illustrates an aquaculture system (1) includingfish (2). The fish are fed either by a centralised feed system such as acanon feed system (3) (shown in FIG. 1) or a hopper system (4) (shown inFIG. 2).

A sensor (5) is positioned at a depth below the normal feeding depth ofthe fish. A funnel (6) collects a sample of the feed passing through theaquaculture system. The sensor is able to obtain information relating tothe amount of feed and through cable (7) is able to relay information toa control unit (8) including computer data storage media. The controlunit is able to regulate the feed metered from the centralised feedingsystem, such as the common feeder of FIG. 1, or the hopper feeder ofFIG. 2, through a connection (9). Connection (9) may be handwired, radiocontrolled or other means, depends upon the particular arrangements.

Feed (10) is distributed by the centralised feeder, and a portion of itwill pass through funnel (6). Information relating to that feed, isdetermined by the sensor and relayed to the control unit.

FIG. 3 illustrates a graphical representation of a feeding pattern. Aminimum feed may be dispensed to the fish and if the amount of feeddetected by the sensor is below a predetermined value, an increasedamount of feed is then dispensed. This is shown graphically with thefeed output increasing over time. This will continue until apredetermined maximum feed output is reached and a minimum pauseinterval between feeds is reached. Once the amount of feed detected bythe sensor is above a pre-determined value, the feed output willdecrease until satiation of the fish is detected. At that time thesystem will withhold feeding until a feeding pattern is detected.

The system will then sleep for a period until a feeding cycle isdetected again The sleep period may be predetermined, or calibrateddepending upon previous feeding cycles learnt by the control unit.

A correlation between the sensitivity of the system, and the pellets perminute is shown in FIG. 4.

FIG. 5 shows an enlarged embodiment of a sensor arrangement, as shown inFIGS. 1 and 2. It shows a sensor (5) incorporated into a funnel (6) byuse of bolts (11) and attached to ring (12). A cone (13) may be placedwithin the funnel to assist in ensuring that a sample of the objectpasses through the aperture (14) of the sensor. The funnel may besuspended by ropes (15)

The underwater funnel (6) and sensor (5) is connected electronically, orby fibre optic cable, to the control unit. The sensor itself may beexternal of the aquaculture system but should be such that it is able todetect the amount of feed passing through the system. The sensor shouldbe positioned in such a way to establish the end of the feeding periodwithout wasting food. This may be achieved by a combination ofadjustments to several algorithm parameters (sensitivity and time ofdelay and spatial and/or temporal arrangements of the sensor).

FIG. 6 illustrates a typical feeding process, monitored by the computerdata storage media. It assumes a spatial feed distribution, and that thepellet density remains reasonably constant. Water current information isprogrammed into the system and considered when distributing the feed Thesensor is also positioned so as to take the largest possible sample ofuneaten pellets

Finally it is to be understood that various alterations, modificationsor additions may be introduced into the system of the present inventionpreviously described without departing from the spirit or ambit of theinvention.

We claim:
 1. A feeding method for cultured species including:(a)providingi) a sensor able to detect feed particles passing through asample area; and ii) a control unit, including computer data storagemedia in communication with the sensor; and (b) detecting anddiscriminating feed particles that pass through the sample area;whereinthe control unit is able to process information obtained from the sensorand regulate subsequent feed output based on algorithm parameters, saidalgorithm parameters determine the instantaneous feed rate of thecultured species to adjust and match the preferred feed values meted tothe cultured species at any given time.
 2. A feeding method according toclaim 1 wherein the sensor is able to discriminate between feedparticles from other matter that may pass through the sample area.
 3. Afeeding method according to claim 1 wherein the control unit is able tostore the feeding history of the cultured species and calculate anoptimum feed regime based on the stored history, and optionally otherinputed parameters.
 4. A feeding method according to claim 1 wherein thecontrol unit is able to regulate the feed output meted to the culturedspecies.
 5. A feeding method according to claim 4 wherein the feedoutput is regulated by at least the following steps:(a) dispensing theminimum feed value to the cultured species; (b) determining the amountof feed particles passing through the sample area; (c) evaluating thenumber of feed particles in the sample area relative to a predeterminedvalue and adjust subsequent output accordingly by:(i) increasing thefeed output if the number of feed particles is below a predeterminedvalue; (ii) maintaining the feed output if the number of feed particlesare within a predetermined threshold; (iii) decrease the feed output ifthe number of feed particles are above a predetermined value ordiscontinue feeding if the number of feed particles are above apredetermined minimum value.
 6. A feeding method according to claim 5wherein the feed is dispensed from a feed dispenser, operated for aperiod of from half a second to 60 seconds, with interval between feedsranging from 1 second to 5 minutes.
 7. A feeding method according toclaim 4 including the further steps of:(a) prior to dispensing theminimum feed value, establishing the relevant information relating tothe setting of algorithm parameters; (b) calibrating the sensor todetermine spatial configuration relating to the sample area; and (c)following the dispensing of a feed value, comparing and adjusting thecalibration of the sensor to compensate for uncalibrated objects.
 8. Afish feeding method according to claim 1 wherein the sensor is anysensor capable of measuring the change in flux of particles passingthrough a sample area, including measurement by optical, ultrasonic orother doppler effect.
 9. A fish feeding method according to claim 1wherein the sensor includes:(i) a body having an aperture orientated inuse to allow objects to pass therethrough; (ii) at least one lightemitter for projecting a band of light across the aperture; (iii) atleast one light receiver for detecting the amount of light passingacross the aperture;wherein in use, the profile of an object passingthrough the aperture is determined ratiometrically by measuring theinstantaneous change in light level caused by the occlusion of light bythe object.
 10. A feeding method according to claim 9 wherein the sensorfurther includes collimating mirrors to direct the light from the lightemitter to the light receiver.
 11. A feeding method according to claim 9wherein real-time analysis of the profile of the object passing throughthe aperture allows for discrimination between feed particles and otherobjects passing through the aperture and to determine the rate of whichthe feed particles pass through the aperture.